Method and system for regulating core body temperature

ABSTRACT

A method for maintaining and/or increasing body temperature of a patient may involve delivering heat to a first location on a limb of the patient, delivering heat to a second location on the limb, apart from the first location, and applying intermittent compression to a third location on the limb, located between the first location and the second location. A device for maintaining and/or increasing body temperature of a patient may include a sleeve for positioning over at least part of one of the patient&#39;s limbs, first and second heat delivery members coupled with the sleeve, and an intermittent compression member coupled with the sleeve between the first and second heat delivery members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/776,791, entitled “Method and System for Regulating CoreBody Temperature,” which was filed on Mar. 12, 2013. Theabove-referenced provisional patent application is hereby incorporatedinto the present application in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

This invention was made with Government support under contract TR001085awarded by the National Institutes of Health. The Government has certainrights in the invention.

FIELD OF INVENTION

The present application relates to medical devices and methods. Morespecifically, the application relates to methods, devices and systemsfor regulating body temperature of a mammal.

BACKGROUND

Each year, over 60 million surgical procedures are performed in theUnited States. While great care is taken to prevent surgicalcomplications, one overlooked and under-addressed problem is the risk ofdeveloping hypothermia before, during or after surgery (referred to as“inadvertent perioperative hypothermia” or “IPH”). Patient temperaturescan drop precipitously during surgery, due to the effects of generalanesthesia, lack of insulating clothing, and exposure to cold operatingroom temperatures. Even with today's standard of care, 30-50% ofsurgical patients will develop hypothermia.

Hypothermia often causes much more than patient discomfort. Patients whosuffer even mild hypothermia are at significantly elevated risk fordeveloping surgical site infections, cardiac morbidities, and othercomplications. Together, these significantly increase recovery time andoverall length of hospital stay, leading to increased costs for allparties. By some estimates, unmanaged risk for IPH is a $15 billionproblem in the United States alone, and yet is largely overlooked.

Perioperative heat loss occurs predominantly via convective heattransfer, particularly through the palms of the hands and soles of thefeet. During preoperative care, patients are dressed solely in a gownand are often exposed to cold waiting areas with little insulation.Therefore, although patients are only anesthetized during surgery,patients often arrive to the surgical theater already slightlyhypothermic. This puts a patient under greater risk for developinghypothermia once anesthesia has been administered. Postoperative dropsin core temperature increase the likelihood of developing additionalmorbidities, such as morbid cardiac outcomes, surgical site infections,and blood loss, any of which typically prolongs recovery andhospitalization.

Patients undergoing surgery are very likely to develop hypothermiaduring the surgical procedure itself, especially when the procedureinvolves their core area, such as procedures involving the thoracic,abdominal, and pelvic regions. Surgeries of the core involve theexposure of vital internal organs to the cooler environment and thuscarry a greater risk of hypothermia. Furthermore, core surgeries oftennecessitate the uncovering of the trunk and chest, which render blanketsand many other existing interventions inadequate. Once in the operatingroom, patients are naked and exposed to a room temperature well below 36degrees Celsius and to cold liquids used to wash the surgical siteduring sterilization preparation. At the onset of surgery, deliveredanesthetics immediately impair the normal autonomic thermoregulatorycontrols. Colder blood is transferred from the peripheries of the bodyto the core through a phenomenon known as redistributive hypothermia.Vasodilatation and reduction in muscle tone cause a significant drop incore temperature within the first half-hour of surgery.

The development of IPH is strongly correlated with a multitude ofphysiological organ system changes, impacting the cardiovascular,respiratory, neurologic, immunologic, hematologic, drug metabolic, andwound healing mechanisms. The incidence of several post-surgicalcomplications is increased due to even mild hypothermia.Intraoperatively, hypothermia can cause a decrease in cardiac output andheart rate, which can lead to ventricular dysrhythmias. Plateletfunctions become impaired and there is a decrease in coagulationfactors, which leads to greater intraoperative bleeding and blood loss.Impaired immune functions increase the rate of surgical site infections.Hypothermia is associated with a four-fold increase in surgical wouldinfection and twice as many morbid cardiac events. These complicationsand others are supported in multiple studies and result in both clinicaland economic burdens.

Overall, compared to non-hypothermic patients, those who suffer IPHexperience greater rates of surgical site infections, bleeding, cardiaccomplications which may require additional monitoring, PACU length ofstay, total length of stay, and subjective discomfort. Although it iscounterintuitive, the likelihood of developing hypothermia in an openversus laparoscopic surgery is similar across various types ofprocedures, most likely attributable to the fact that most laparoscopicprocedures are significantly longer when compared to their open surgerycounterpart.

Current methods of preventing hypothermia are not completely effective.Even with the current interventions, up to 46% of patients are reportedto be hypothermic at the start of surgery and 33% are hypothermic uponarrival to the PACU. Assuming the cost savings for maintainingnormothermia in one patient is approximately $5,000 per patient, andapproximately 30% of the 17 million high-risk surgical patients arehypothermic, a system-wide cost savings of $15 billion will be realizedby keeping these patients normothermic. With rising healthcare costs andrecent initiatives by CMS mandating the maintenance of perioperativenormothermia, hospital administrators nationally are in need of new,efficacious and cost-effective devices to address perioperativehypothermia, a product space which has seen little innovation since theintroduction of the forced air warming blanket nearly three decades ago.

Currently available devices for perioperative warming are primarilyforced air warming blankets. In particular, the Bair Hugger™ device(Arizant Healthcare, Inc.) is the most commonly used technology and isused in 85% of U.S. hospitals. Newer alternatives include high-heattransfer conduction heating blankets and intraoperative hand warmingdevices. Although these devices are somewhat effective, they all haveseveral key shortcomings: (1) They are cumbersome, and thus complianceand correct usage is low; (2) Warming in the intraoperative period aloneis significantly less effective than warming preoperatively andintraoperatively; and (3) Devices that heat via the core of body areineffective during surgeries of that anatomical area. Currentlyavailable devices are often not used or not practical for use inpreoperative warming for one or more of the following reasons: (1) Theyimmobilize the upper limbs; (2) They are cumbersome—e.g., they float onthe patient and get blown off during implementation and transport andthey require large, predominantly floor-based blowers that are notmobile; (3) They are not attached to the patient and become dislodgedduring transport and obstruct the bed and other monitors and devices;and/or (4) They require a conscious administrative decision toimplement. This has been shown to take up to 30 minutes to deployeffectively in clinical studies. A busy and stressed preoperative nursecannot afford this time.

Additionally, currently available patient warming devices are often notused for any of the above reasons and/or any of the following reasons:(1) Fear of contaminating surgical field—e.g., forced air methods canblow bacteria containing air onto the surgical field; (2) Forced airblankets get in the way—e.g., to warm the core, they need to be incontact with the core; and/or (3) Operating room staff may turn down thetemperature on the device due to their own comfort—e.g., operating roomstaff turns down the patient's forced air due to air escape heating thesurrounding staff.

Therefore, it would be advantageous to have improved methods and systemsfor maintaining a patient's core body temperature before, during and/orafter surgery. Ideally, such methods and systems would be easy to set upand use, unobtrusive and effective. Also ideally, such methods andsystems would be suitable for use before, during and after a surgicalprocedure and would be acceptable to the patient while awake in thepreoperative and postoperative settings. At least some of theseobjectives will be met by the embodiments described herein.

BRIEF SUMMARY

Devices, systems and methods described herein are directed towarddelivering thermal energy and/or blood flow regulating therapy to apatient to help regulate body temperature. In many embodiments, adevice, system and method involves delivering both thermal energy andblood flow regulating therapy to the body. Blood flow regulation istypically used in the systems, devices and methods described herein tohelp return blood to the core of the body from one or more extremities.This blood flow regulation therapy may be accomplished in a number ofdifferent ways, such as but not limited to intermittent compressionand/or electrical stimulation. In some embodiments, a device is appliedto a lower or upper limb, and the device delivers heat to at least onearea and blood flow regulation therapy to at least one area on the lowerlimb. In one specific embodiment, for example, a body temperatureregulation device may deliver heat to two different areas on a limb andintermittent compression near the one or both of the two areas. In onespecific embodiment, heat is delivered to the popliteal fossa (posterioraspect of the knee) and sole of the foot, and intermittent compressionis delivered to an area between the popliteal fossa and the foot.

In one aspect, a method for maintaining or increasing body temperatureof a patient may involve delivering heat to a first location on a limbof the patient, delivering heat to a second location on the limb, apartfrom the first location, and applying intermittent compression to athird location on the limb, located between the first location and thesecond location. In some embodiments, the limb is a lower limb, thefirst location is a popliteal fossa of the lower limb, and the secondlocation is a sole of a foot of the lower limb. In some embodiments, theheat is delivered and the compression is applied to both lower limbs ofthe patient. In some embodiments, the heat and compression may bedelivered and applied to the first, second and third locations at thesame time. Alternatively, the heat and compression may be delivered andapplied to the first, second and third locations at least two differentstarting times and/or for at least two different lengths of time.

In some embodiments, the heat delivery and compression application stepsare performed by one device having heat delivery and intermittentcompression capabilities. In alternative embodiments, the heat deliveryand compression application steps may be performed by multiple devices.Optionally, these multiple devices may be connected to a common controlunit configured to control operation of the multiple devices.

The method may optionally further involve adjusting positioning of atleast a portion of at least one of a heat delivery device or acompression device on the limb to change at least one of the firstlocation, the second location or the third location. In variousembodiments, the heat may be delivered in the form of ultrasound,electrical, mechanical, chemical, radiative and/or convective energy. Invarious embodiments, applying intermittent compression may involveapplying electrical stimulation, mechanical compression and/oracupuncture.

In some embodiments, the method may further involve measuring atemperature of the patient, a temperature of a heat delivery deviceand/or an amount of compression applied to the patient. Such a methodembodiment may optionally further involve adjusting at least one of theheat delivery or the intermittent compression, based on the measurement.The method may further involve, before the heat delivery and compressionapplication steps, placing a sleeve over at least part of the limb,where the sleeve includes heating and compression members. The methodmay also optionally involve forming a vacuum between the sleeve and thelimb, before delivering the heat or applying the compression.

In various embodiments, the heat delivery and compression applicationsteps may be performed during a time period before a surgical procedureis performed on the patient, during performance of the surgicalprocedure on the patient, and/or after performance of the surgicalprocedure on the patient. In some embodiments, the method may beperformed on a patient who has a condition such as but not limited tolymphedema, deep vein thrombosis, peripheral artery disease, muscularconditions or disorders, or a heightened risk of any of theseconditions.

In another aspect, a device for maintaining or increasing bodytemperature of a patient may include a sleeve configured for placementover at least a portion of a foot and a portion of a leg of the patient,a first heat delivery member coupled with the sleeve such that it ispositioned over a popliteal fossa of the patient when the sleeve isplaced over the leg, at least a second heat delivery member coupled withthe sleeve such that it is positioned over a sole of the foot when thesleeve is placed over the foot, and at least one intermittentcompression member coupled with the sleeve such that it is positioned inan area between the first and second heat delivery members when thesleeve is placed over the leg and the foot. In various embodiments, theheat delivery members deliver energy in a form of ultrasound,electrical, mechanical, chemical, radiative or convective energy. Insome embodiments, the intermittent compression member comprises at leastone expandable bladder. Alternatively, the intermittent compressionmember may include at least one pressure chamber.

Optionally, the device may also include a controller coupled with thesleeve for controlling at least one of heat delivery or compressionapplication by the device. Such embodiments may also optionally includeleast one temperature sensor for sensing a temperature of the patient,and a connection between the at least one temperature sensor and thecontroller to provide sensed temperature data to the controller. In someembodiments, the controller may include a feedback loop configured tocontrol the heat delivery members and the compression member, based onthe sensed temperature data.

The sleeve may include multiple compartments, and the heat deliverymembers and the intermittent compression members may be disposed in thecompartments. In some embodiments, at least one of the heat deliverymembers is moveable relative to its location on the sleeve to adjust itslocation on the limb. Optionally, the intermittent compression membermay also be moveable relative to its location on the sleeve to adjustits location on the limb. The first heat delivery member, the secondheat delivery member and/or the intermittent compression member may belongitudinally moveable relative to the other members along the sleeveto adjust locations of the members relative to one another, in someembodiments.

The device may also include a wicking material on an inner surface of atleast part of the sleeve to help wick moisture away from skin of thelimb. The device may also include a suction device coupled with thesleeve to provide a vacuum between an inner surface of the sleeve andthe limb. The device may also include an adhesive on at least a portionof an inner surface of the sleeve to provide adhesion between the innersurface and skin of the limb. All of these are optional features, whichmay be included on various embodiments.

In another aspect, a system for maintaining or increasing a bodytemperature of a patient may include: a first heat delivery memberconfigured for positioning over a popliteal fossa of a lower limb of thepatient; at least a second heat delivery member configured forpositioning over a sole of the foot of the lower limb; at least oneintermittent compression member configured for positioning on the lowerlimb between the popliteal fossa and the foot of the limb; at least oneheat source couplable with the first and second heat delivery members;and at least one compression source couplable with the at least oneintermittent compression member. Optionally, the system may also includea sleeve configured for placement over at least a portion of the lowerlimb, including at least a portion of the foot and the popliteal fossa,where the first heat delivery member, the second heat delivery memberand the intermittent compression member are coupled with the sleeve.

The system may also include at least one connector for connecting theheat source with the first and second heat delivery members and forconnecting the compression source with the at least one compressionmember. For example, the at least one connector may comprise multipleconnectors joined together along at least a portion of their lengths. Insome embodiments, the system may also include a controller coupled withthe at least one heat source and the at least one compression source,for controlling delivery of heat and application of compression to theleg and the foot. In some embodiments, the controller, the at least oneheat source and the at least one compression source are housed in one,combination device. In some embodiments, the combination device may beconfigured to attach to a side of a bed. Optionally, the system mayfurther include at least one temperature sensor for sensing atemperature of the patient and at least one connector connecting the atleast one temperature sensor to the controller, so that the sensedtemperature can be conveyed to the controller.

These and other aspects and embodiments will be described in furtherdetail below, in references to the attached drawing figures.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagrammatic representation of a body temperature regulationsystem, according to one embodiment;

FIG. 2 is a diagrammatic representation of a body temperature regulatingsystem, according to an alternative embodiment;

FIGS. 3A and 3B are perspective and posterior views, respectively, of alower limb of a human with a body temperature regulation system in placeon the lower limb, according to one embodiment;

FIGS. 4A and 4B are perspective and posterior views, respectively, of alower limb of a human with a body temperature regulation system in placeon the lower limb, according to an alternative embodiment;

FIG. 5 is a perspective view of a lower limb of a human with a bodytemperature regulation system in place on the lower limb, according toanother alternative embodiment;

FIG. 6 is a perspective view of a lower limb of a human with a bodytemperature regulation system in place on the lower limb, according toanother alternative embodiment;

FIG. 7 is a perspective view of a lower limb of a human with a bodytemperature regulation system in place on the lower limb, according toanother alternative embodiment;

FIG. 8 is a posterior view of a lower limb showing another alternativeembodiment of a body temperature regulating system;

FIG. 9 is a posterior view of a lower limb showing another alternativeembodiment of a body temperature regulating system;

FIG. 10 illustrates one embodiment of a foot-positioned component of abody temperature regulation system;

FIG. 11 illustrates an alternative embodiment of a foot-positionedcomponent of a body temperature regulation system;

FIGS. 12-15 are bottom views of a sole of a foot, illustrating variousalternative embodiments of a foot-positioned component of a bodytemperature regulating system; and

FIGS. 16A and 16B are bottom views of a sole of a foot, illustratinganother alternative embodiment of a foot-positioned component of a bodytemperature regulating system.

DETAILED DESCRIPTION

The following disclosure describes various embodiments of a method,device and system for regulating body temperature of a mammal. Thevarious embodiments generally combine delivery of heat with delivery ofblood flow regulation therapy to increase and/or maintain bodytemperature. Although the blood flow regulation therapy most describedbelow is intermittent compression, in alternative embodiments, differenttypes of blood flow regulation therapy may be used, such as electricalstimulation. The embodiments are typically, though not necessarily,configured for use on a limb of a patient. Although the followingdescriptions focus primarily on use of the methods, devices and systemson a lower limb (i.e., leg and foot) of a human patient, in alternativeembodiments, the methods, devices and systems may be used on an upperlimb, on a lower limb and upper limb, on two lower or two upper limbs orany other combination. In still further embodiments, methods, devicesand systems may be alternatively or additionally used on a torso orother anatomical region of a patient. Additionally, although theembodiments are generally described for use in delivering heat tomaintain and/or increase body temperature, alternative embodiments maybe used for cooling the body.

FIGS. 1 and 2 are diagrammatic depictions of two embodiments of a bodytemperature regulating system. Referring now to FIG. 1, in oneembodiment, a body temperature regulating system 100 may include a bodyinterface member 101, a blood flow regulation member 102, a thermalenergy transfer member 103, a connector 104 and a central unit 107. Eachof these components of system 100 may be single components or multiplecomponents, according to various embodiments. For example, bodyinterface member 101 may be one sleeve that fits over a limb or multiplesleeves, according to alternative embodiments. Blood flow regulationmember 102 may be one heat delivery device or multiple heat deliverydevices, according to alternative embodiments. The same is true of theother components. Therefore, although each component is referred toherein in the singular, each may actually include multiple devices,components, parts or the like.

Body interface member 101 is configured to attach to a patient and tocontain or otherwise attach to blood flow regulation member 102 andthermal energy transfer member 103. All of these features will bedescribed in further detail below. In general, in some embodiments, bodyinterface member 101 may include one or more sleeves that fit over atleast a portion of a lower limb (or upper limb in alternativeembodiments). Blood flow regulation member 102 may include one or morecompression members for delivering compression to a portion of the bodywith which it comes into contact. In some embodiments, this compressionis delivered intermittently. Thermal energy transfer member 103 mayinclude one or more heat delivery members for delivering heat to one ormore areas of the limb. In one embodiment, for example, body interfacemember 101 may fit over a portion of the lower limb, including at leastpart of the popliteal fossa, at least part of the sole of the foot, andan area between the two. Thermal energy transfer member 103 may includea heat delivery member at the popliteal fossa and another heat deliverymember at the sole of the foot. Blood flow regulation member 102 mayinclude one intermittent compression member attached to body interfacemember 101 in a location between the two heat delivery members ofthermal energy transfer member 103. This is only one example, however,and many alternatives are possible.

Connector 104 may include any suitable connector or combination ofconnectors for transferring any combination of thermal energy,electrical power, a fluid, data and/or the like between body interfacemember 101 and central unit 107. Central unit 107 may include, forexample, a source of thermal energy, a source of compression force, orboth. Intermittent compression may be delivered in the form of air thatinflates a bladder of blood flow regulation member 102, for example. Insome embodiments, central unit 107 may include two or more separatedevices, such as a thermal energy source and a separate source ofcompression force. In alternative embodiments, central unit 107 may beonly one device. In alternative embodiments, system 100 may include onlythermal energy transfer member 103, only blood flow regulation member102, or any combination of components.

With reference now to FIG. 2, an alternate embodiment of a bodytemperature regulating system 110 may include a body interface member111, a blood flow regulation member 112, a thermal energy transfermember 113, a connector 114 and a central unit 117, as described inrelation to the embodiment above. Additionally, system 110 may include acontrol unit 118 and a sensor 119. Sensor 119, for example, may sense apatient's body temperature, the temperature of a heat delivery member,and/or the like. Any suitable temperature sensor may be used, and anysuitable number of sensors may be attached to interface member 111, forexample. Control unit 118 may be coupled with, and may receive sensedinformation from, sensor 119. Control unit 118 may then transmit signalsto central unit 117 to adjust delivery of heat and/or compression to apatient, according to the sensed temperature data from sensor 119. Inmany embodiments, control unit 118 may be combined with central unit 117in one device or “box.” For example, one device or box may be used, insome embodiments, to (1) deliver thermal energy, (2) deliverintermittent compression force, and (3) control the delivery of thermalenergy and compression. In some embodiments, the same device or box mayalso be used to receive sensed signals from one or more sensors and usethose signals as feedback for controlling the delivery of thermal energyand compression. In other embodiments, any one or more of thesefunctions may be performed by one or more separate devices.

FIGS. 1 and 2 are block diagrams, illustrating components of twoembodiments of a system 100, 110 for regulating patient temperature. Inalternative embodiments, components may be added, removed or changed,and/or connections of the components may be altered. In someembodiments, one component of the system may be provided separately as adevice for use with another system or device. Furthermore, in variousembodiments, the system may be placed on a single, multiple, or anycombination of extremities of the body where peripheral blood flow ispresent. The word “extremities,” as used herein, refers to the arms,legs, head and neck. As mentioned previously, in various embodiments,the systems described herein may be applied to any extremity, portion ofan extremity or combination of multiple extremities. Alternativeembodiments may be used with other parts of a patient, such as thetrunk. Therefore, although the following description focuses on variousembodiments for use on one or both lower limbs of a patient, theseembodiments are provided only as examples.

Referring now to FIGS. 3A and 3B, perspective and posterior views,respectively, of a portion of a human leg L illustrate one embodiment oftemperature regulation system 100 in a position for use. Body interfacemember 101, in this embodiment, includes multiple sleeves that fit overthe leg L and foot of the patient, and that are attached via multiplestraps 105, such as Velcro straps. Thermal energy member 103 includestwo heat delivery devices (each labeled 103), which are attached tointerface member 101 so as to be located at the popliteal fossa(posterior portion of the knee) and on a portion of the sole of thefoot. Blood flow regulation member 102 includes one intermittentcompression delivery device attached to interface member 101 so as to belocated between the two thermal energy members 103. Central unit 107 isconnected to the rest of system 100 via connector 104, to providethermal energy delivery and compression force delivery. In FIG. 3,connector 104 is illustrated for simplicity as one connector 104.However, in embodiments like the one shown, where there are threeseparate body interface members 101 and thus three separate componentsto provide thermal energy and compression, three connectors 104 wouldactually be connected to central unit 107 to provide thermal energy andcompression to the three separate components.

In use, thermal energy is transferred from thermal energy transfermembers 103 through the tissue to the peripheral arterial and venousblood. Alternately, the energy transfer may flow in the oppositedirection, from the peripheral blood through the tissue to the thermalenergy transfer members 103 (e.g., to reduce body temperature). Throughthe transfer of thermal energy in the peripheral blood, the core bodytemperature may be regulated as the peripheral blood returns to thecore. Locating thermal energy transfer members 103 in locations on thebody where thermal energy transfer to the peripheral blood is mostefficient can improve the efficiency the system. This allows forsufficient thermal energy transfer while minimizing the body surfacearea required for device coverage. In various alternative embodiments,locations for positioning thermal energy transfer members 103 mayinclude the entire extremity or may be limited to the popliteal fossa,sole of the foot, ankle, groin, palm of the hand, wrist, armpit, neck,head, or any portion(s) or combination(s) of these locations.

The various embodiments of systems and methods for the transfer ofthermal energy to the body described herein may include any means ofintroducing or extracting thermal energy. Specific examples of thermalenergy introduction include electrical energy, electromagnetic energyincluding light, lasers, radiation, or induction, convective transferthrough a liquid such as air or water, chemical energy such as from anexothermic chemical reaction, acoustic energy such as ultrasound orhigh-intensity focused ultrasound (HIFU), mechanical energy such asvibration, or any other energy transfer method/system now known ordiscovered in the future. Additionally, in some embodiments, the systemsand methods may induce physiological thermal production through anincrease in metabolism and/or by stimulating physiological responsesfrom blunt or sharp trauma. Thermal energy may be efficiently extractedfrom the body through the use of a heat sink or heat sinking materials,or by the application of cold media to the body.

In various embodiments, body interface member 101 (multiple pieces inthe embodiment of FIGS. 3A and 3B) may be made of any suitable material.Ideally, such material will be breathable and/or repel moisture. Someexamples of materials may include, but are not limited to, polyethylene,polyvinyl chloride, or other polyesters, either woven or non-woven. Insome embodiments, the regulation of core body temperature via thermalenergy transfer members 103 may be enhanced through the modulation ofperipheral blood flow via one or more blood flow regulation members 102.Blood flow regulation member 102, which in the pictured embodimentcomprises an intermittent compression device, may be a part of system100 applied to the leg L or other extremity. By regulating the venousreturn of the peripheries in which thermal energy has been transferred,system 100 can enhance its thermal regulation of the body core. This canincrease the efficiency of system 100 and allow for regulation of thecore body temperature with a smaller, less intrusive system located onthe extremities of the body.

As just mentioned, blood flow regulation member(s) 102 may provide forthe application of force or compression to the muscles of the extremityin order to enhance the venous return. In some embodiments, blood flowregulation member(s) 102 include intermittent compression devices, suchas air bladders with compartments that fill and empty repeatedly tosqueeze the body tissue. As this type of air bladder intermittentcompression device is well known currently, it will not be describedfurther here. However, any such currently known intermittent compressionbladder device or any such device developed in the future may be used invarious embodiments of system 100.

In various alternative embodiments, blood flow regulation member(s) 102may include sequential compression devices, mechanical squeezing orforce application through tightening of a sleeve around the extremity,mechanical alteration or stretching of skin, delivery of one or morepharmacological agents, or a combination thereof. Any of theseembodiments may include one or multiple chambers filled with a fluid,such as air, water, or a high specific heat gas or liquid. Blood flowregulation member(s) 102 that provide for application of force may beintermittent or continuous. Intermittent compressive force may includesequential application, including random or patterned application orwave application, including sinusoidal, square, forward and/or reversewave patterns.

In alternative embodiments, blood flow regulation may additionally oralternatively involve causing local vasodilation, and blood flowregulation member(s) 102 may include one or more devices designed topromote vasodilation. Blood flow regulation member(s) 102 for promotinglocal vasodilation may act through a metabolite, a hormone, or thenervous system, creating hypoxia, or the application of a vacuum, forexample. In other alternative embodiments, blood flow regulation mayadditionally or alternatively involve promoting muscle contraction. Suchmethods may include active stimulation such as electrical musclestimulation or acting on the peripheral nervous system. Alternatively,methods may include passive contraction through pharmacological means orthrough applied movement to the extremity.

With continued reference to FIG. 3, system 100 may be applied to thebody (leg L or other extremity) by way of body interface member 101,which may include one or more housings and/or one or more sleeves.Interface member 101 is generally configured to provide stability,comfort, and ease of motion for ambulatory patients, as well as properfit and interface between system 100 and the body. This helps ensureproper function of other components in system 100, including thermalenergy transfer member 103 and blood flow regulation member 102.Interface member 101 may include and enclose body worn electronics for amobile and wireless system, including but not limited to a power source,circuit board, sensors such as temperature and pressure, and/or wirelesscommunication devices. It may also include pipes, tubing, one ormultiple pumps, heating elements, cloth, and/or other components. Bodyinterface member 101 may include a sleeve, blanket, wrap, patch and/orthe like. Proper fit and function may be ensured through the use ofadhesives or stickers. Additionally, body interface member 101 mayinclude a portion, or multiple portions, that extend internally into thepatient, for example into a subdermal or subcutaneous layer of the body.Body interface member 101 may be multi-layered, providing thermal orelectrical insulation, thermal or electrical conduction, forceapplication, electrical connection, or other features in differentlayers of the interface. In various alternative embodiments, thecomponents of system 100 may be housed in a single or multipleenclosures of body interface member 101, such as pockets. The componentsof system 100 may directly contact the patient's skin in someembodiments, and alternatively there may be a layer of body interfacemember 101 between one or more of the components and the skin, forexample if one or more components are housed in one or more pockets ofbody interface member 101. Also in various alternative embodiments, bodyinterface member 101 may be worn directly on the skin surface orexternally/outside of clothing.

Body interface member 101 may be attached to the patient's leg L orother extremity by any suitable means, such as but not limited to one ormore attachment members coupled with interface member 101. In theembodiment shown in FIG. 3, for example, multiple straps 105 are used asa means to ensure system 101 is easy to apply, remains in place duringthe working life, and is easy to remove when necessary. System 100 mayinclude straps or other attachment means that use Velcro, magnets,string, ties, clips, elastic bands and/or the like. System 100 alsoincludes one or more connectors 104, to transfer any combination ofthermal energy, electrical power, a fluid, and/or data between bodyinterface member 101 and central unit 107. For simplicity ofillustration, only one connector 104 is illustrated in FIG. 3A. In FIG.3B, three connectors 104 are shown—two connectors 104 a for deliveringthermal energy to thermal energy transfer members 103, and one connector104 b for delivering compression force to blood flow regulation member102. In various embodiments, connectors 104 a, 104 b may connect withone central unit 107 or with multiple devices. Connectors 104 may alsotransmit sensed data from one or more sensors 119 (not shown) on bodyinterface unit 101 to central unit 107. For example, one or moretemperature sensors may be coupled with body interface unit 101 to sensebody temperature. Central unit 107 may be body worn on the patient insome embodiments or located separate from the patient, as shown.Connectors 104 and central unit 107 may be separate for each devicelocated on a different extremity or combined for an entire system actingon one or multiple extremities.

As discussed above in reference to FIG. 2, system 100 may include othercomponents as well. These include but are not limited to controller 118and one or more sensors 119 (neither of which is shown in FIGS. 3A and3B). Sensors 119, such as temperature sensors, may measure core,peripheral, skin, tissue, and/or blood temperatures. Informationtransmitted from sensors 119 to controller 118 may be used by controllerto adjust system 100 to modulate thermal energy transfer. Additionallyor alternatively, one or more sensors 119 may be configured to determineblood flow, and controller 118 may also use such blood flow informationto adjust system 100. Controller 118 may act in system 100 to controlthe function and/or output of other components, including but notlimited to thermal energy transfer members 103 and/or blood flowregulation member 102. Controller 118 may receive data and feedback fromthe components it is controlling and may also receive data and feedbackfrom sensors 119.

Sensors 119 may provide for data acquisition to determine thefunctionality and effects of system 100. Specifically, such data mayinclude, but is not limited to, temperature data such as core,peripheral, skin, tissue, and/or blood temperature. This data may beprovided to controller 118, thermal energy transfer member 103, a userinterface internal or external to system 100 (laptop computer, desktopcomputer, or the like, for example), a data acquisition device internalor external to system 100, another component or piece of equipmentinternal or external to system 100, or any combination of these.Similarly, other data may be acquired by sensors 119, including bloodflow measurements, and utilized in a similar manner to that describedfor temperature sensors.

Additionally, system 100 may include a user interface (not shown) toprovide a means in which a user can turn on or off different componentsof system 100 or input settings such as desired temperature and to allowsystem 100 to output data to a user such as temperature or blood flowsettings and/or readings. System 100 may also provide feedback to theuser that may include alarms, data, information, or messages given via ascreen, light, sound, or tactile feedback. System 100 may additionallyinclude communication equipment to allow various system components tocommunicate in wired or wireless fashion and/or to allow communicationbetween system 100 and other, external devices or systems, includinghospital equipment, computers, printers, etc. System 100 may alsoinclude a power source, which in some embodiments may be coupleddirectly with another component of system 100 and worn by the patient,thus not requiring attachment to any power outlet. Such a power sourcemay include one or multiple batteries, for example. System 100 may alsoinclude the ability to switch between battery and outlet power to allowfor mobile and ambulatory use. System 100 may also utilize other sourcesof power, such as but not limited to power from the building supply orwireless power such as inductive power, solar, or power derived frommechanical movement.

In various alternative embodiments, system 100 may include any suitablecombination of the components described above. In some embodiments, infact, one single component may be provided as a device, which may becoupled with and used with system 100 or some other, alternative system.Specifically, various embodiments of system 100 may include one or morethermal energy transfer members 103 only, one or more blood flowregulation members 102 only, a combination of thermal energy transfermember(s) 103 and blood flow regulation member(s) 102 components as partof the same system, a combination of thermal energy transfer member(s)103 and blood flow regulation member(s) 102 as part of separate devices,thermal energy transfer member(s) 103 used in conjunction with otherexisting devices, including those meant to regulate blood flow, or anyother combination of the components described herein. These may includea device consisting of one or multiple thermal energy transfer members103 that can be worn with existing deep vein thrombosis (DVT)prophylaxis devices, such as compression socks or sequential compressiondevices (SCD) or similar devices for other conditions. Therefore, thedescriptions of embodiments herein as “devices” and/or “systems” shouldnot be interpreted as limiting the scope of the invention due to anyparticular use of the terms “device” and “system.”

Referring now to FIGS. 4A and 4B, in an alternative embodiment, a bodytemperature regulation system 110 may include all the same components asdescribed in relation to the previous embodiment, except that a bodyinterface member 111 may be one, continuous sleeve, rather than multiplesleeves. Such a sleeve/interface member 111 may be pulled on over thefoot and up onto the leg L, like a long sock. Such an interface member111 may be made of any suitable material. Ideally, such material will bebreathable and/or repel moisture. Some examples of materials mayinclude, but are not limited to, polyethylene, polyvinyl chloride,Neoprene, elastic, nylon, Spandex, other polyesters, combinations of anyof these materials or the like. Interface member 111 may also be eitherwoven or non-woven. Straps 115, such as Velcro straps, may be used tofurther secure interface member 111 with the skin. Coupled withinterface member 111 are thermal energy transfer members 113, blood flowregulation member(s) 112, connector 114 and central unit 117. Althoughmultiple connectors 114 a and 114 b are illustrated in FIG. 4B, in oneembodiment these connectors 114 a, 114 b may be combined into oneconnector 114, as illustrated in FIG. 4A. In such a one-connectorembodiment, thermal energy and/or compression force or other blood flowregulation energy may be transferred through body interface member 111to the various components. Not shown, but optionally included in system110, may be a controller 118 and one or more sensors 119.

In any of the embodiments described herein, thermal energy transmissionmember 113 may include two heat delivery members, one configured forpositioning over at least part of the popliteal fossa and one configuredfor positioning over at least part of the sole of the foot. Alternativeembodiments may include fewer or more thermal energy transmissionmembers 113, and these embodiments may be configured for positioning onother anatomical locations on the patient. Regulating temperature at thepopliteal fossa and sole of the foot, however, may be a very effectiveand efficient way to regulate a patient's body temperature. In theseembodiments, blood flow regulation member 112 may be one intermittentcompression delivery member, configured for positioning on the patient'slower limb between the two thermal energy transmission members 113 onthe foot and the popliteal fossa. For example, blood flow regulationmember 112 may be positioned on the calf. This combination of thermalenergy delivery to the popliteal fossa and sole of the foot, along withintermittent compression delivery to the calf, may be a very effectiveway to increase and/or maintain a patient's body temperature and thusprevent inadvertent perioperative hypothermia.

The embodiment of FIG. 4 may have a number of advantages over anembodiment having a multi-piece body interface member. For example, itmay be easier to apply and remove one body interface member 111, ascompared to multiple members. Additionally, it is possible to use onlyone connector 114 in such an embodiment, since thermal energy and/orintermittent compression force may be transferred through body interfacemember 111 to thermal energy transfer member(s) 113 and blood flowregulation member(s) 112. On the other hand, in some cases it may beadvantageous to have several, separate body interface members 101 (FIG.3), with separate components attached to each. For example, it may beeasier to apply and remove smaller, separate body interface members 101.In some cases, it may be desirable to use only a subset of the separatecomponents, either by themselves or in conjunction with another device,such as a currently available intermittent compression or heat deliverydevice. Therefore, various different embodiments may be advantageous indifferent circumstances.

With reference now to FIG. 5, another alternative embodiment of a bodytemperature regulation system 120 may include two body interface members121, each of which is coupled with one or more thermal energy transfermembers 123 and is secured to the patient via one or more straps 125.Thermal energy transfer members 123 are housed in separate bodyinterface members 121—one for the popliteal fossa and one for the soleof the foot and ankle. These components may be used together,separately, or with and other components herein. Obviously, system 120is not illustrated with any connectors or central units, but these maybe provided as part of system 120 or may be part of another system withwhich system 120 may be used. In one embodiment, system 120 illustratedin FIG. 5 may be the same as system 100 illustrated in FIG. 3, exceptwithout blood flow regulation member 102.

Referring now to FIG. 6, in another alternative embodiment, a bodytemperature regulation system 130 may include a thermal energy transfersock 131, coupled with a connector 134 and attached to the lower limbvia a strap 135. Connector 134, of course, may be coupled with a centralunit, controller, or combined central unit/controller, as describedabove but not illustrated here. In this embodiment, system 130 does notinclude a blood flow regulation member. However, sock 131 may becombined with a blood flow regulation members, such as an intermittentcompression device, in some embodiments. For example, a compressiondevice may be applied over sock 131 in some embodiments. Sock 131 may bemade of any suitable material, such as but not limited to those listedabove in reference to the various embodiments of body interface members.

With reference to FIG. 7, yet another alternative embodiment of a bodytemperature regulation system 140 may include a body interface member141 attached to the limb via one or more straps 145, multiple thermalenergy transfer members 143, and multiple blood flow regulation members142. In this embodiment, multiple thermal energy transfer members 143are positioned on the sole of the foot and behind the ankle, and anotherthermal energy transfer member 143 is positioned at the popliteal fossa.Blood flow regulation members 142 are configured as strips, and eachstrip houses one or more electrodes, which are used to stimulate tissueand promote muscle contraction. These electrode strips are positionedboth above and below the popliteal fossa, although in alternativeembodiments only one set of strips in one location may be used.

FIG. 8 is a posterior view of a lower limb showing another alternativeembodiment of a body temperature regulating system 150. In thisembodiment, system 150 includes a body interface member 151 that fitsover most or all of the lower limb, blood flow regulation member 152comprising two strips of electrodes, a thermal energy transfer member153 comprising two heat transfer elements, and a connector 154. Variousfeatures, details and alternatives described above in relation to otherembodiments may be applied to this embodiment as appropriate.

FIG. 9 is a posterior view of a lower limb showing another alternativeembodiment of a body temperature regulating system 160. In thisembodiment, system 160 includes a body interface member 161 that fitsover most or all of the lower limb and that acts as a thermal energytransfer member 163, similar to (or identical to) the embodimentdescribed above as a heat transfer sock. System 160 also includes ablood flow regulation member 162 comprising three strips of electrodes,a first connector 164 a leading to thermal energy transfer member 163,and a second set of connectors 164 b leading to blood flow regulationmembers 162. Various features, details and alternatives described abovein relation to other embodiments may be applied to this embodiment asappropriate.

FIG. 10 illustrates one embodiment of a foot-positioned component 170 ofa body temperature regulation system. In this embodiment, component 170includes a body interface member 171, such as a sock-like member, and athermal energy transfer member 173. Thermal energy transfer member 173does not cover all of the foot in this embodiment but is disposed over aportion of the sole of the foot and the back of the ankle.

FIG. 11 illustrates an alternative embodiment, in which afoot-positioned component 180 of a body temperature regulation systemcomprises a combined, sock-like body interface and thermal energytransfer member.

FIGS. 12-15 are bottom views of a sole of a foot, illustrating variousalternative embodiments of a foot-positioned component 190, 200, 210,220 of a body temperature regulating system. In each embodiment,foot-positioned component 190, 200, 210, 220 includes a body interfacecomponent 191, 201, 211, 221 and a thermal energy transfer component193, 203, 213, 223. As these figures illustrate, any of a number ofdifferent configurations may be used in various embodiments of afoot-positioned of a body temperature regulating system. Specifically,various embodiments may be configured to help ensure comfort and/orfacilitate a patient's ability to walk while using the system. Forexample, as illustrated in the embodiment of FIG. 12, a bottom surfaceof thermal energy transfer unit 193 (or additionally or alternativelybody interface member 191) may include tacky or gripping materials onthe soles of the feet or palms of the hand to ensure safety and functionduring use.

FIGS. 16A and 16B are bottom views of a sole of a foot, illustratinganother alternative embodiment of a foot-positioned component 230 of abody temperature regulating system. In this embodiment, foot-positionedcomponent 230 includes a body interface component that has multiplelayers 231 a, 231 b, 231 c and a thermal energy transfer component 233.The various layers 231 a, 231 b, 231 c may be made of any suitable,conformable material, such as but not limited to those previously listedabove.

As mentioned previously, any individual component of the systemembodiments described above may be located in a single location orcombination of locations. These locations may include those on the bodyof mammals. As described previously, the thermal energy transfercomponent may be located continuously along the extremity or in separatelocations ideal for thermal energy transfer. These may include locationswhere there is high blood flow, where the artery or vein is close to theskin surface, and/or where there is little interference with requiredclinical access. These include, but are not limited to, the hands, feet,neck, and major arteries and veins of the extremities including thefemoral, popliteal, saphenous, tibial, pedal, axillary, brachial,cubital, radial, ulnar, cephalic, jugular, carotid arteries and veins.Blood flow regulator components may be placed in any single orcombination of locations to regulate blood flow of the arteries andveins described above.

Any of a number of embodiments of methods for regulating bodytemperature may be performed, using the systems described above. Thesemethods may be used not only for the prevention of hyperthermia, butalso for the maintenance of normothermia, the maintenance of therapeutichypothermia, the maintenance of therapeutic hyperthermia, the recoveryfrom hypothermia in both environments internal and external to thehospital, and/or recovery from hyperthermia in both environmentsinternal and external to the hospital. For example, in one embodiment, amethod may involve positioning a thermal energy transfer member over atleast part of the popliteal fossa and at least part of the sole of thefoot, positioning an intermittent compression member or other blood flowregulation member in an area of the lower limb between the two thermalenergy transfer members, and providing heat and compression force to thelower limb using the system.

Various embodiments of these methods for body temperature regulation mayinvolve, for example: (1) Transferring thermal energy and/or regulatingblood flow for the control of core body temperature through theextremities, including but not limited to the arms, legs, face, palm ofthe hand, sole of the foot, neck and head; (2) Transferring thermaltherapy in conjunction with or independently of blood flow regulationtherapy prior to induction of anesthesia. The thermal therapy maycontinue in conjunction with or independently of blood flow regulationtherapy after the induction of anesthesia; Transferring thermal energyand/or regulating blood flow continuously or intermittently, includingrandom or patterned application. (4) Transferring thermal energy and/orregulating blood flow at varied time intervals, which may or may not bein synchronization with one another; (6) Transferring thermal energypreoperatively in order to prevent hypothermia before induction ofanesthesia and after induction due to redistribution hypothermia; (7)Transferring thermal energy preoperatively as described above andcontinuing thermal energy transfer and/or blood flow regulation inintraoperative and/or postoperative settings; and/or (8) Transferringthermal energy and/or regulating blood flow for the control of core bodytemperature in order to benefit patients with or at risk of lymphedema,deep vein thrombosis, peripheral artery disease, muscle conditions, orany other suitable condition.

Although this invention has been described in detail, the scope of theinvention as set forth in the following claims should not be limited bythe foregoing descriptions of various embodiments. Thus, it is intendedthat the scope of the present invention herein disclosed should not belimited by the particular disclosed embodiments described above, butshould be determined only by a fair reading of the claims that follow.

What is claimed is:
 1. A method for maintaining or increasing core bodytemperature of a patient, the method comprising: placing a first bodyinterface member comprising a first electrical thermal energy transfermember over a knee on a lower limb of the patient, such that a positionof the first electrical thermal energy transfer member is limited to apopliteal fossa on a posterior aspect of the knee; placing a second bodyinterface member comprising a second electrical thermal energy transfermember over a foot of the lower limb, such that the second electricalthermal energy transfer member extends over a sole on a bottom surfaceof the foot of the lower limb; placing a third body interface membercomprising at least one intermittent compression inflatable bladder inan intermediate location on the lower limb between the first and secondbody interface members, such that the at least one intermittentcompression inflatable bladder is spaced apart from the first electricalthermal energy transfer member and the second electrical thermal energytransfer member; delivering heat to the popliteal fossa with the firstelectrical thermal energy transfer member, the heat delivery by thefirst electrical thermal energy transfer member being limited to thepopliteal fossa; delivering heat to the sole of the foot with the secondelectrical thermal energy transfer member, the heat delivery by thesecond electrical thermal energy transfer member being limited to thesole of the foot; and applying intermittent compression and not heat tothe intermediate location on the limb with the at least one intermittentcompression inflatable bladder, wherein intermittent compression isapplied to the lower limb only by the at least one intermittentcompression inflatable bladder, wherein delivering heat to the poplitealfossa and the sole of the foot and applying intermittent compression tothe intermediate location maintains or increases the core bodytemperature of the patient.
 2. The method of claim 1, wherein the heatis delivered to the popliteal fossa and the sole of the foot at the sametime, and wherein the intermittent compression is applied to theintermediate location at the same time that the heat is delivered. 3.The method of claim 1, wherein the heat and compression are deliveredand applied at at least two different starting times and for at leasttwo different lengths of time.
 4. The method of claim 1, furthercomprising measuring at least one of a temperature of the patient, atemperature of at least one of the body interface members, or an amountof compression applied to the patient, using a measurement device on atleast one of the first body interface member, the second body interfacemember or the third body interface member.
 5. The method of claim 4,further comprising adjusting at least one of the heat delivery or theintermittent compression, based on the measurement.
 6. The method ofclaim 1, wherein the first, second and third body interface members arecombined in one sleeve.
 7. The method of claim 1, wherein the heatdelivery and compression application steps are performed during at leastone time period selected from the group consisting of before a surgicalprocedure is performed on the patient, during performance of thesurgical procedure on the patient, and after performance of the surgicalprocedure on the patient.
 8. A method as in claim 1, wherein the patienthas a condition selected from the group consisting of lymphedema, deepvein thrombosis, peripheral artery disease, muscular conditions ordisorders, and a heightened risk of any of these conditions.